Photoelectron escape depth

The average escape depth of Al 2s and O 1s photoelectrons is determined for the Al/Al(oxide) system experimentally and theoretically (Monte Carlo simulations [1], analytical solution of the kinetic equation in the transport approximation [2]). Special attention is paid to a particular experimental geometry where pronounced effects of elastic scattering are expected [1]. The first results show that for the asymmetry parameter being equal to 2 and the emission directions close to that of x-ray propagation, the mean escape depth of electrons may differ noticeably from the value predicted by the usual XPS formalism (when elastic scattering is neglected). The results obtained may be of special practical interest in quantitative XPS analysis and transmission photoelectron microscopy.